Labyrinth seal



H. .9. WOOD LABYRINTH SEAL Original Filed Sept. 17, 1949 INVENTOAArroz/VE# United States Patent LABYRINTH SEAL Homer J. Wood, ShermanOaks, Calif., assignor to The Garrett Corporation, Los Angeles, Calif.,a corporation of California Original application September 17, 1949,Serial No. 116,370, now Patent No. 2,684,196, dated `luly 26, 1954.Divided and this application April 25, 1952, Serial No. 284,423

Claims. (Cl. 286-10) The present invention relates generally to animproved labyrinth seal construction and method of making the same, andlinds particular use in compact high velocity turbine driven units ofthe type utilized for air conditioning and refrigeration, especially inaircraft.

The present application constitutes a division of my copendingapplication, Serial No. 116,370, filed September 17, 1949, now issuedPatent No. 2,684,196.

It is one object of the herein described invention to provide improvedsealing means for the turbine end of the unit.

Further objects and advantages of the invention will be brought out inthe following part of the specification wherein a detailed disclosure ofthe invention is made for the purpose of disclosing one embodimentthereof without limiting the scope of the invention.

Referring to the drawings which are for illustrative purposes only:

Fig. l is an end elevational view of the turbine end of the unit,portions being cut away to disclose internal constructional details;

Fig. 2 is a fragmentary sectional view, taken substantially online 2 2of Fig. 1;

lFig. 3 is a detailed sectional view through the turbine end sealingmember, taken substantially on line 3 3 of Fig. l, and

Fig. 4 is an enlarged fragmentary sectional view showing details of thelabyrinth seal around the turbine end of the shaft.

Referring now to the drawings, for illustrating purposes there is shownin Fig. 1 a fan unit containing a labyrinth seal constructed accordingto the present invention.

Briefly as shown primarily in Figs. 1 and 2, the unit embodies a mainhousing and a turbine end casing 77 secured thereto as by securingscrews 80. A seal member 17 of generally disc like construction issecured between the main housing and turbine end casing, the seal memberbeing afxed to the housing 10 as by screws 75 which pass throughopenings 73 and threadedly engage threaded sockets 76 in an end flange61 -of the main housing cooperatively associated with a peripheralflange 62 of the seal member.

The seal member centrally contains a tubular hub 54 which defines atubular bore 55 for reception of the main shaft 27 of the unittherethrough, the shaft within the tubular bore 54 being provided withan annular member 31 which may, if desired, constitute a hub portion ofa slinger or fan element (not shown) of the bearing lubricating system,or comprise simply a shaft collar.

The details of the labyrinth seal at the turbine end of the unit betweenthe hub 31 and hub 54 of the seal member 17, will now be explained.Referring to Fig. 4, the bore 55 of the hub 54 is coated with a lining102 of a composition containing lead, -or other suitable compositionwhich has a suitable plastic ow characteristic. The hub 31 has its outersurface formed with a plurality of spaced circnmferentially extendinggrooves 103 2,781,210 Patented Feb. 12, 1957 firice defining spacedlands 104. As initially fabricated, the internal diameter of the lining102 is made slightly less than the outside diameter of the lands 104. Toassemble and complete the labyrinth seal, the seal member'17 issupported in axially aligned position by the screws which are instarting position in the threaded sockets 76, such that as these screwsare tightened, the lining 102 will pass over the grooved surface of thehub 31.

The sharp edges of the lands 104 will thus'act as cutting members toprovide a tubular inner surface of uniform diameter on the lining andgive a broached Iit between the lining and surface'of the lands. Theparts are then disassembled and cleaned to remove any particles ofmetal, and then again assembled. Upon subsequent operation of the unit,the surface contact of the lands with the inner surface of the liningapplies pressure and heat to the composition comprising the lining 102and causes plastic flow deformation which bulges the material of thelining into the grooves 103 slightly and thus forms a labyrinth seal andtakes care of any slight eccentricity which might be present. -It isthis slight eccentricity and slight axial movements of the shaft and hub31, inherent during operation of the rotating structure, that causesengagement of the edges of the lands 104 with the lining 102 so as toresult in the plastic ow, as explained above.

=I claim:

1. The method of forming a labyrinth seal between adjacent parts ofrelatively rotatable members adapted to operate in concentric relationwhich comprises lining the surface of one of said members with amaterial having a plastic ow characteristic, forming circumferentialgrooves defining spaced projecting rings in the other surface,assembling the members by relative axial movement and breaching saidmaterial with said rings to provide a broached tit, and thereafter owingthe lining into the grooves between the rings as a result of slightrelative eccentric movements between the members upon relativelyrotating said members.

2. The method of forming a labyrinth seal between adjacent parts ofrelatively rotatable members adapted to operate in concentric relationwhich comprises lining the' surface of one of said parts with a materialcontain-` ing lead having a plastic ow characteristic, formingcircumferential grooves defining spaced projecting rings in the surfaceof the other member, broaching the lining surface of one part byrelative axial movement of the members whereby the broached surfaceconforms to the periphery of the rings, and thereafter flowing thelining into the grooves between the rings as a result of slight relativeeccentric movements between the members upon relatively rotating saidmembers.

3. The method of forming a labyrinth seal between adjacent surfaces ofrelatively rotatable members adapted to operate in concentric relation,one of said members having a surface lined with a material having aplastic flow characteristic and the other having a circumferentiallygrooved surface dening spaced projecting rings, the initial relativediameters `of the lining surface and the rings being such that the ringsproject past the lining surface, which comprises the steps of: initiallyassembling the members by relative axial movement so as to broach thelining surface with the rings; and thereafter flowing the lining intothe grooves between the rings as a result of slight relative eccentricmovements between the members upon relatively rotating said members.

4. A seal structure, comprising: a shaft; a wall member having a centralbore for the passage of said shaft; a tubular bore lining having aninner surface of initially uniform diammer, said lining being ofmaterial having a plastic ow characteristic; and means carried by theshaft having spaced circumferentially extending surface grooves denngannular lands adjacent the. inner surface of said bore lining, saidlands upon initial assembly of "said shaft Within said wall memberhaving a broached t References Cited in the Vle of this patent UNITEDSTATES YPATENTS 888,064 Chambers May 19, 1908 15 4 Wood. Apr.' *18.191,6 Loomis Sept. 4, 1923 Huhn June 16, 11936 Keller Oct. 27, 1936 HuhnMar. 7, 1939 Warren Dec. 7, #1943 McKnight Jan. 23, 1945 FOREIGN PATENTSGreat Britain July 29, 1940 I l l l

